Transport Properties of Fluids and Mixtures

The transport properties of fluids and mixtures govern the transfer of momentum, heat and mass within and between phases. These include viscosity, which measures resistance to shear; thermal conductivity, the capacity to conduct heat; and diffusion coefficients, which quantify molecular mixing. Such properties arise from intermolecular interactions and thermodynamic state variables, notably temperature, pressure and composition. Accurate determination is essential for design and optimisation across sectors from energy processing to pharmaceuticals, climate modelling and microfluidics. Advances in experimental techniques, computational methods and theoretical frameworks have refined our understanding, enabling predictive models that bridge molecular-scale behaviour and macroscopic phenomena. Key approaches encompass residual entropy scaling, corresponding states methods and statistical associating fluid theories, each linking thermophysical properties to equations of state. Integration of these models within process simulators facilitates robust design of reactors, pipelines and heat exchangers, while emerging machine-learning tools offer new avenues for rapid estimation in complex multicomponent systems.

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Transport Properties of Fluids and Mixtures publication trend

The graph below shows the total number of articles in transport properties of fluids and mixtures across all publications each year (not limited to Nature Index journals).

Technical terms

Viscosity: A measure of a fluid’s resistance to deformation under shear stress, reflecting momentum transport between layers.

Thermal conductivity: The capacity of a material to conduct heat, determined by energy transfer at the molecular level.

Residual entropy: The difference between actual entropy and that of an ideal reference state, used as a scaling variable for transport properties.

Equation of state (EoS): A thermodynamic relation linking pressure, temperature and volume, foundational for calculating residual properties.

Self-diffusion coefficient: A parameter quantifying the rate of molecular migration in a pure or multicomponent fluid, indicative of mass transport.

References

1. Linking Viscosity to Equations of State Using Residual Entropy Scaling Theory. International Journal of Thermophysics (2022).
2. Combining the entropy-scaling concept and cubic- or SAFT equations of state for modelling thermal conductivities of pure fluids. International Journal of Heat and Mass Transfer (2022).
3. Modeling Self-Diffusion Coefficient and Viscosity of Chain-like Fluids Based on ePC-SAFT. Journal of Chemical & Engineering Data (2023).